Chemistry Test 73

Humans can produce 10 of the 20 amino acids. The others must be supplied with food. Failure to obtain enough of even 1 of the 10 essential amino acids, those that we cannot make, results in degradation of the body's proteins—muscle and so forth—to obtain the one amino acid that is needed. Unlike fat and starch, the human body does not store excess amino acids for later use—the amino acids must be in the food every day.

The 10 amino acids that we can produce are alanine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, proline, serine, and tyrosine. Tyrosine is produced from phenylalanine, so if the diet is deficient in phenylalanine, tyrosine will be required as well.

Hence, the correct option is (A).

Since in this colloidal mixture, a solid is mixed with another solid, the molecules are having a tight bond between them. Hence it is called a solid sol. Solid sol is the colloidal dispersion that is solid in the state but is a little soft. When they are boiled for 5-6 min, they become softer. Gemstones are an example of solid sol.

Hence, the correct option is (A).

A known mass of the organic compound is heated in the presence of pure oxygen. The carbon dioxide and water formed are collected and weighed. The percentages of carbon and hydrogen in the compound are calculated from the masses of carbon dioxide and water. The estimation of carbon and hydrogen in an organic compound is based on their conversion to CO, and H₂O respectively. The percentage of carbon and hydrogen is calculated from the masses of CO₂ and H₂O.

The apparatus consists of a long glass tube. This is called a combustion tube. To one end of this tube, a U-tube containing anhydrous calcium chloride and a bottle containing concentrated potassium hydroxide solution (caustic potash) are attached in series. These, in turn, are connected to a guard tube containing anhydrous calcium chloride.

Hence, the correct option is (C).

The IUPAC name of (NH₄)₂[Ni(C₂O₄)₂(H₂O)₂ ]is ammonium daiquiris(oxalate)nickelate(II). It has an oxalate ion as a central atom.

Oxalate ion is a bidentate ligand even though it contains four O atoms that have lone pairs of electrons. In this complex, two oxalate ions are bonded to the Ni atom. The coordination number of 4 results in a square planar structure.

Hence, the correct option is (A).

BeH₂, MgH₂  is the pairs of hydrides that are polymeric in nature. Dihydrogen will combine with almost all elements, except Noble gases under certain reaction conditions forming binary compounds that are popularly called hydrides and these hydrides can be expressed as EHx (e.g., CaH₂) or EmHn (e.g.,B₂H₆) where ‘E’ is the symbol of the element. 

Hence, the correct option is (A).

Paramagnetic species contain unpaired electrons in their molecular orbital electronic configuration. The molecular orbital configuration of the given species is as 

The given structure is Peroxymonosulphuric acid. The image is shown below:

Peroxymonosulfuric acid, (H₂SO₅), also known as persulfuric acid, peroxysulphuric acid, or Caro's acid. In this acid, the S(VI) center adopts its characteristic tetrahedral geometry; the connectivity is indicated by the formula HO–O–S(O)₂–OH. It is one of the strongest oxidants known (E₀ = +2.51 V) and is highly explosive.

H₂SO₅ is sometimes confused with H₂S₂O₈, known as peroxydisulfuric acid. The disulfuric acid, which appears to be more widely used as its alkali metal salts, has the structure HO–S(O)₂–O–O–S(O)₂–OH.

Hence, the correct option is (C).

According to the VSEPR theory, The shape of the molecule is determined by both the total number of electron pairs (bonding and non-bonding) around the molecule's central atom and the orientation of these electron pairs in the space around the central atom.

In order to minimize the repulsion forces between them, electron pairs around the molecule's central atom, tend to stay as far away from each other as possible.

Xe has electronic configuration 5s² 5p⁶.

XeF₂ molecular geometry is linear. It acquires such shape as the lone pairs present around the central atom tend to take up equatorial positions. The bond angle is said to be 180°. The hybridization of XeF₂ is sp³d.

XeF₄ consists of two lone pair electrons. Now if we follow the VSEPR theory, the net electronic repulsions has to be minimum. With this, they will acquire a stable state. In order to achieve this, the lone pairs lie in a perpendicular plane in an octahedral arrangement opposite (180 degrees) from each other. Therefore, XeF₄ molecular geometry is square planar. The hybridization is sp³d².

This means there are a total of three bond pairs and one lone pair. Therefore there will be three hybrid orbitals (three for bond pair and one for lone pair). To form these hybrid orbitals one s and three p orbitals will be used. So, the hybridization of this XeO₃ molecule is sp³. Geometry is trigonal bipyramidal.

XeO₄ has geometry due to sp³ hybridization. The shape is Tetrahedral.

Hence, the correct option is (C).

Partial reduction of phenyl cyanide with stannous chloride and passing dry HCl gas in ether solution followed by hydrolysis of the aldimine stannic chloride with water to form benzaldehyde is called Stephan’s reaction. The reaction mechanism is given as follows:

Hence, the correct option is (D).